Sydney scientist regrows monkey's heart with stem cells

Nicky Phillips

An Australian-led team has for the first time regenerated heart muscle in several primates by grafting specialised tissue grown from human embryonic stem cells, a procedure that could be trialled in humans with heart failure in a few years.

Researchers injected about a billion heart muscle cells onto the hearts of seven pigtail macaque monkeys to repair damage caused by a heart attack, which kills large numbers of the organ's muscle cells.

Of 111 NFL players examined, 110 had this disease

Australian scientist first to regrow heart muscle

A team led by Australian cardiologist James Chong is the first in the world to regenerate heart muscle grown from human embryonic stem cells, which could lead to a cure for heart failure.

The breakthrough procedure offers a potential therapy for people with chronic heart failure, which kills more than 20,000 Australians each year, and could replace the need for heart transplants in these people.

The cardiologist who conducted the experiments, James Chong, from the University of Sydney and the Westmead Millennium Institute, said with further research and funding he hoped to start clinical trials in humans in a few years.

Cardiologist David Ross, a professor at the University of Sydney who was not involved in the study, said if the technique proved safe and effective in the long term it could "transform the treatment of heart failure".

While scientists have previously coaxed embryonic stem cells into heart cells, or cardiomyocytes, this was the first time a significant number of these cells have been successfully transplanted into a large animal.

Advertisement

"We were able to show for the first time that from two weeks after transplantation these human heart muscle cells were beating synchronously with the host heart of a large animal," said Dr Chong, who collaborated with researchers at the University of Washington.

They found up to 40 per cent of the damaged region of the heart regenerated and that blood vessels from the host heart were supplying the grafted muscle with nutrients.

You will now receive updates fromTechnology Daily Newsletter

Technology Daily Newsletter

"We showed much more re-muscularisation than any other studies," he said.

The results were published in the leading scientific journal, Nature.

To mimic the damage done to the heart by a heart attack, the researchers restricted blood flow to an artery in the monkey's heart, which is similar in size and beat rate to a human's, while it was under anaesthetic in laboratories in the US.

Two weeks later they inserted heart muscle cells, differentiated from human embryonic stem cells in the laboratory, into the damaged region of the monkey's heart during open heart surgery.

The muscle cells were tagged with a marker that glowed green when they beat.

"That gave us a unique tool to track the function of these humans cells after they’d been transplanted in the monkey," he said.

"We weren’t sure how it was going to pan out but when we first saw that green we were elated."

Although the monkeys appeared healthy after the procedure, some did develop arrhythmias, abnormal heart rhythm, which would require further investigation, Dr Chong said.

The group also demonstrated the heart muscles cells still functioned after being cryo-preserved, which would be essential for any large-scale therapeutic use in humans.

"If a patient comes in with a heart attack they’re not going to know when," Dr Chong said.

"Cryo-preserving allows you to produce them in bulk beforehand and freeze them and have them on tap."